What is an SPF Record?
January 06th 2009
An SPF record is a small text file that tells ISPs who you are, and
what domains you will send legitimate email from. You publish this file
on your DNS server and more and more frequently, an incomplete or
inaccurate SPF Record will cause your emails to be blocked by the
recipients Internet Service Provider (ISP).
Your SPF record should include information about your domain and the
domains of any third-party e-mail service providers you use.
How does it work?
Any time an e-mail is sent, the receiver’s mail server checks the
domain name in the "From" field of the email message. If it matches any
of the domains listed in the sender’s SPF record, the mail is
authenticated and delivered to the receiver. If there is not a match
with the published SPF record or the SPF record doesn’t exist, the mail
fails authentication and is not delivered.
I have spoken at length on may occasion to System Administrators about SFP records and Sender-ID etc and this is not the explanation I got from people who actually use them and manage them as part of an ESP.
We know the net is often full of misleading information but for people who do not know any better it might be all you can find?